Project Abstract Sugar Alert is a 4-year study to assess the impact of the first-ever sugar-sweetened beverage (SSB) warning labeling policy on knowledge, attitudes and consumption. SSB consumption is a major contributor to the twin epidemics of obesity and diabetes in America.1 Starting July 25 2016, the City of San Francisco will require prominent warning labels on most SSB advertisements: WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay. This is a message from the City and County of San Francisco.? Because San Francisco is the first jurisdiction to apply a warning label to SSBs, the proposed study offers an unprecedented opportunity to document if and how this approach could provide a viable tool for obesity prevention. Warning labels are a mainstay in evidence- based tobacco and alcohol policymaking. They have proven effective in changing attitudes, knowledge and the consumption of tobacco and to a lesser extent, alcohol, and therefore hold great promise for obesity prevention. The proposed study will examine how consumers understand and react to warning labels on advertisements, whether this increases knowledge about the health harms of SSBs, promotes negative attitudes towards SSBs, or reduces SSB consumption. The effects of race/ethnicity, income, health consciousness and cognitive processing of the message will be assessed. We propose a pre-post quasi-experimental design with a representative telephone panel survey, including a pre-implementation baseline observation and follow-ups at 6, 12 and 24 months post-baseline. We will follow a representative sample of 1100 San Francisco adults and 1100 residents of San Jose as a control jurisdiction. Latinos and blacks, two ethnic groups with higher rates of SSB consumption, obesity and diabetes, will be oversampled to analyze whether warning labels disproportionately impact these vulnerable populations. Subjects will be screened for cross-contamination through travel. A complementary study component that documents all forms of advertising visible in both SF and SJ locations will assess compliance and advertiser responses to the warning label, validate whether implementation occurs as intended by lawmakers, and will detect shifts away from regulated advertising by advertisers seeking to circumvent the label effects. Specific Aims of the study are to: 1) Aim 1. Assess the exposure of San Francisco?s residents to the warning label message by documenting implementation over time. 2) Aim 2. Assess exposure to warning labels in SF (and SJ) adults over time, and whether exposure is associated with changes in knowledge, attitudes and behavior pertaining to SSBs and whether changes affect subpopulations differently, 3) Aim 3. Examine whether San Franciscans exposed to warning labels on SSB advertising report more pronounced reductions in daily calories consumed from SSBs compared to San Jose residents over time.